Samba High Availability

[Selick, Matthew]

Here at ITT Avionics, we have Samba installed on a Dec (now Compaq)
TruCluster. It works great! Better than an NT cluster, in many respects.
There are a couple of tricks that you need to know. Someone may want to put
this in a FAQ somewhere or some document, as it might be useful to someone.

	1. Use smbd -D -s /somepath/cluster.conf or nmbd -D -s
/somepath/cluster.conf when you start up your smbd and nmbd daemons. Don't
use the default smb.conf path that is compiled in.
	2. create that cluster.conf file to look something very much like
this:

		# To edit the cluster services, remove and relink
/usr/local/samba/lib/smb.conf
				# to the /somepath/netbios_name.conf file of
your choice and then
				# use swat to reconfigure.


				# Need this so that Samba can authenticate
with the correct domain
				# All of the rest of the information is in
the netbios name of the
				# cluster service, followed by .conf
				workgroup = YOUR_WORKGROUP_HERE


				# This line will include the correct
configuration file for the
				# particular cluster service:
				include = /somepath/%L.conf

	3. When using SWAT, don't use it to modify your cluster.conf file,
change the /usr/local/samba/lib/smb.conf file to link to whichever cluster
service you want to modify.
	4. Create service configuration files, one for each "virtual server"
that you have. The %L in the cluster.conf will point to the Netbios name for
the virtual machine.

The only problem that I see with this whole setup is that locking
information doesn't get transferred over to the other system when a cluster
failover occurs. This is not an issue for us here, since we usually only
have one user accessing a file at a time.

I have been using this solution for about 2 years now, on various different
versions of Samba. I am running 2.0.5a for Samba and 4.0-f and TCR1.6 right
now for Compaq Tru64 Unix (formerly Dec OSF). I don't know how it would play
with Solaris, HP, Linux, etc., but I would love to hear from you to find out
what you decide to do.

Matthew G. Selick
UNIX/NT System Administrator
ITT Avionics
Matt at Selick.com
(973) 284-4744